Paint Gauges

[Calendyr]

Hello everyone,



my first real post here, was trying to think of something to post about and I think this is the perfect subject to get my feet wet on this forum



So, I don't have a paint gauge yet. It's the next item on my buy list.



Thing is, I feel like this is more of a toy to look good than an actual useful tool.



The reason I feel this way is that everytime I have seen people posting about the amount of paint they took off doing correction, the number is always very small...

from 1 to 6 microns.



And when people talk about paint thickness, I think the lowest number I have seen so far was 80 microns.



So... assuming that out of that 80 microns, there is at least 20 microns of clearcoat (really worst case scenario in my book)... what does it matter if we take out an average of 3 microns? There will be plenty of it left.



The only useful thing I can think of for a paint gauge would be for wet sanding.



So my question is, I am completelly wrong about this and if so, what am I missing?



Do you guys use paint gauges on a regular basis and where there situations where you did not want to do a paint correction because of paint thickness?

 

[Ron Ketcham]

For the average, DIY person, it's a crap shoot.

As a professional, before I retired, working with the vehicle manufactuers, one is necessary.

Used them since the early 90's, was even part of the test development for Pro-Motor Car ETG units.Presently I still own a ferrous readout and a dual readout unit for ferrous and aluminum substrates.

I use them a lot, just like a doctor or such, do the test before moving forward.

What I don't understand is that the people who do use them, insist on using micron readings rather than mil readings.

Not many vehicle manufacturers use micron, they use for dealer and their field service people only "mil" readings.

If you can afford one, buy one, doesn't have to be a big dollar one, just one that gives a less than 5% error factor.

 

[Calendyr]

For the average, DIY person, it's a crap shoot.

As a professional, before I retired, working with the vehicle manufactuers, one is necessary.

Used them since the early 90's, was even part of the test development for Pro-Motor Car ETG units.Presently I still own a ferrous readout and a dual readout unit for ferrous and aluminum substrates.

I use them a lot, just like a doctor or such, do the test before moving forward.

What I don't understand is that the people who do use them, insist on using micron readings rather than mil readings.

Not many vehicle manufacturers use micron, they use for dealer and their field service people only "mil" readings.

If you can afford one, buy one, doesn't have to be a big dollar one, just one that gives a less than 5% error factor.

Well, microns are a lot more precise. Why would you use feets instead of inches when you want to be precise? I understand that mills are the common way of evaluating paint thickness, but microns are about 20 times more precise.



So have you had situations where you were unable to do a correction because the paint was too thin?

 

[Ron Ketcham]

Yes, they are more precise, but then we are not using surgical instruments to remove paint film.

Use of microns for cutting/polishing is overkill.

That is why the vehicle manufacturers, for the most part, do not refer to them for film removal.

 

[Ron Ketcham]

Have I had situations where the total film build was to thin?

Well, been on the professional side of the business, working with 9 of the largest vehicle manufacturers, with two large auction chains, thousands of dealers, traveled the world to aid in paint/trim/corrosion concerns for the manufacturers, being it to consult or diagnois and to provide products with correct procedures, etc ---a few thousand times I found lack of correct film build which made it not practical to do corrections. Off to the bodyshop area for refinishing, only way to be doing it right.

 

[Accumulator]

..What I don't understand is that the people who do use them, insist on using micron readings rather than mil readings...

You and I have, uhm.... :argue about this one before Just a "different strokes.." thing IMO. I simply find the microns easier to process when I'm doing evaluation/correction.



BUT, ya know.. I find mils easier when evaluating a used-vehicle for purchase :nixweiss



[QUOTE+Calendyr]So have you had situations where you were unable to do a correction because the paint was too thin? [/QUOTE]



Yeah, both on my vehicles and some of the (very few) that I've done for others recently.



Best example: I was doing a pal's restored Jag, and if I hadn't taken a zillion readings I would've overdone some sections where the clear was much thinner than on the rest of those panels. Try as I might, I couldn't *see* most of the diffs, but the readings alerted me and one area would've been a serious disaster. Later found out that the painter had wetsanded some flaws out of that area ("Oh yeah, you noticed that?..didn't think to tell you..").

 

[Calendyr]

You and I have, uhm.... :argue about this one before Just a "different strokes.." thing IMO. I simply find the microns easier to process when I'm doing evaluation/correction.



BUT, ya know.. I find mils easier when evaluating a used-vehicle for purchase :nixweiss



[QUOTE+Calendyr]So have you had situations where you were unable to do a correction because the paint was too thin?

Yeah, both on my vehicles and some of the (very few) that I've done for others recently.



Best example: I was doing a pal's restored Jag, and if I hadn't taken a zillion readings I would've overdone some sections where the clear was much thinner than on the rest of those panels. Try as I might, I couldn't *see* most of the diffs, but the readings alerted me and one area would've been a serious disaster. Later found out that the painter had wetsanded some flaws out of that area ("Oh yeah, you noticed that?..didn't think to tell you..").[/QUOTE]



Ok, good to know. Do you remember the readings in the areas that were too thin?

 

[Accumulator]

Ok, good to know. Do you remember the readings in the areas that were too thin?

You mean on the restored Jag, right? Nope, been too long. But it was a case of certain sections of a panel reading *way* under what the rest of the panel was. This car was tricky as it had a mix of preps, from bare metal to repaint-over-old paint and some panels were redone more than once, some were spot-repaired after the resto...all sorts of stuff to consider. His (black) Porsche is even worse, I've been avoiding doing it for a few years but might end up tackling it some day :nervous:

 

[Jean-Claude]

I just spent 40 hours on some paint and the PDG was absolutely necessary. Some areas were so thin that I refused to follow through with complete removal of defects. Other areas were great. If I just went after defect removal I have no doubt that there would be other problem looming down the road, if not before the end of the job. Most cars are not like that but it does happen from time to time.